CN115012325A - Concrete box girder bridge reinforcing scheme based on FRP (fiber reinforced plastic) section bars - Google Patents

Abstract

The utility model provides a concrete box girder bridge reinforcement scheme based on FRP section, includes concrete box girder, bridge deck pavement layer, concrete box girder bottom FRP section and concrete box girder lateral part FRP section. The concrete box girder is a prefabricated or cast-in-place concrete hollow girder. The bridge deck pavement layer is positioned on the upper part of the concrete box girder; the FRP profiles are spliced and arranged at the bottom and the side of the box girder, are fixed with the box girder by expansion bolts, and are arranged in the span of the bottom of the box girder and arranged on the side of the box girder along the direction of the bridge. The reinforcing scheme of the concrete box girder bridge based on the FRP profiles provided by the invention fully utilizes the advantages of light weight, high strength, corrosion resistance, good designability and the like of FRP materials, effectively reinforces the concrete box girder, improves the integral rigidity and bearing capacity of the bridge on the premise of not increasing the self weight of the bridge, and ensures the safety and reliability of a bridge system.

Description

A reinforcement scheme of concrete box girder bridge based on FRP profiles

technical field

The invention relates to the field of bridge structure reinforcement in civil engineering, in particular to a concrete box girder bridge reinforcement scheme based on FRP profiles.

Background technique

With the acceleration of urban modernization, urban land is tight, and traffic flow has increased sharply. A large number of viaducts and overpasses have been constructed to improve the efficiency of vehicle traffic and greatly ease traffic congestion. Box-section beams are widely used in bridge structures due to their box chambers, light weight, good overall mechanical performance in space and excellent section characteristics.

In many cases, with the increase of service life of box girder bridges, various reasons may cause the decrease of structural rigidity, increase of deflection, and influence on the safe service life of the structure; For reasons such as the update of standards, it may also make it difficult for the existing structures to meet the new requirements. Therefore, it is necessary to reconstruct and strengthen such bridges to improve the safety and durability of highway bridges.

At present, in the reinforcement design of box girder bridges, in order to improve the local unfavorable stress state of the bridge, reduce the number and width of cracks in the beam body, and prolong the life of the structure, the reinforcement scheme includes the application of prestressing technology and the addition of external high-strength materials. The prestressed reinforcement method realizes structural reinforcement by adding additional prestressed steel bars or composite material bars between the beams, and releasing the external force in the tension zone of the box girder by prestressing tension. In the pasting FRP reinforcement method, high-performance fiber reinforced composite material cloth is selected and pasted on the surface of the box girder, so that it can bear the force together with the original component, among which carbon fiber reinforced composite material (CFRP) is mostly used. However, the above scheme is only applicable to the case where the bridge stiffness is sufficient and the structural allowable load remains unchanged.

When the overall stiffness of the bridge structure is insufficient or the bearing capacity needs to be increased, the methods of externally bonded steel reinforcement or outsourced concrete reinforcement are mostly used at present. However, because the steel is easy to corrode in the air, and the maintenance cost is high in the later stage, the outsourcing concrete will greatly increase the dead weight of the structure, and the lower structure of the reinforced bridge has higher requirements. Therefore, there is still a lack of an effective reinforcement scheme that can improve the stiffness of the bridge while taking into account the advantages of corrosion resistance, light weight, and low maintenance costs.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a reinforcement scheme for concrete box girder bridges based on FRP profiles in view of the deficiencies of the prior art.

The technical solutions adopted are:

A concrete box girder bridge reinforcement scheme based on FRP profiles is provided. The concrete box beams are prefabricated or cast-in-place concrete hollow beams, and the outer section forms are one of a rectangle, a trapezoid and a curved edge. The bridge deck pavement layer is located on the upper part of the concrete box girder; the FRP profiles at the bottom of the concrete box girder are arranged at the mid-span position of the bottom of the box girder, and the FRP profiles of the side part of the concrete box girder are arranged at the side span position of the box girder. The layout length is calculated according to the actual reinforcement requirements, and the profiles and the box beams are fixed with expansion bolts.

The FRP profiles include C-shaped FRP profiles, I-shaped FRP profiles, and I-shaped FRP profiles with inclined webs. The flange ends of the profiles need to be prefabricated with external tenons and external sockets, which can be spliced into continuous FRP hollow panels through adhesives.

In the embodiment of the reinforcement scheme for concrete box girder bridges based on FRP profiles provided by the present invention, C-shaped and I-shaped FRP profiles are selected at the bottom of the box girder, and spliced into continuous FRP hollow panels with vertical webs, which are mainly used to bear the deformation caused by the bending moment. Tensile load; I-shaped FRP profiles with C-shaped and inclined webs are selected on both sides of the box girder, and spliced into continuous FRP hollow panels with inclined webs, which are mainly used to bear shear loads.

The reinforcement scheme for concrete box girder bridges based on FRP profiles provided by the present invention, by arranging FRP profiles at the bottom and side of the box girder, takes advantage of the advantages of light weight, high strength, corrosion resistance, good designability, etc. The girder bridge is reinforced to improve the overall stiffness and bearing capacity of the bridge without increasing the self-weight of the bridge, so as to ensure the safety and reliability of the bridge system.

Description of drawings

FIG. 1 is a schematic diagram of the arrangement position of FRP profiles along the bridge direction in an embodiment of the present invention.

2 is a cross-sectional view of a concrete box girder reinforced with FRP profiles in an embodiment of the present invention.

FIG. 3 is a detailed diagram of the types and structures of FRP profiles in an embodiment of the present invention.

Detailed ways

The embodiments of the present invention do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description of the present invention, or directly or indirectly applied in other related technical fields, are similarly included in the present invention. within the scope of patent protection.

A concrete box girder bridge reinforcement scheme based on FRP profiles, the structure includes a concrete box girder 1, a bridge deck pavement layer 2, a FRP profile 3 at the bottom of the concrete box girder, and a FRP profile 4 at the side of the concrete box girder. The concrete box girder 1 is a prefabricated or cast-in-situ concrete hollow beam, and the outer cross-sectional form is one of a rectangle, a trapezoid, and a curved edge. The deck pavement layer 2 is located at the upper part of the concrete box girder 1; the FRP profile 3 at the bottom of the concrete box girder and the FRP profile 4 at the side of the concrete box girder are spliced and arranged at the bottom of the box girder 1 and the side of the box girder 1, respectively. The box beams 1 are fixed with expansion bolts 5 .

In the embodiment of the concrete box girder bridge reinforcement scheme based on FRP profiles provided by the present invention, the FRP profiles 3 at the bottom of the concrete box girder include C-shaped FRP profiles 6 and I-shaped FRP profiles 7, which are mainly used to bear the tensile force caused by the bending moment. Load; FRP profiles 4 on the side of the concrete box girder include C-shaped FRP profiles 6 and I-shaped FRP profiles 8, which are mainly used to bear shear loads. The outer tenon 9 and the outer socket 10 are prefabricated at the flange ends of the FRP profile 3 at the bottom of the concrete box girder and the side FRP profile 4 of the concrete box girder, so that they can be spliced into a continuous FRP hollow panel by adhesive.

When the present invention is used, after selecting the number of the FRP profiles 3 at the bottom of the concrete box girder and the FRP profiles 4 at the side of the concrete box girder with reference to the cross-sectional size of the concrete box girder 1, firstly connect the C-shaped FRP profiles 6 with the outer tenon 9 through the expansion bolts 5 Fixed on one side of the box girder. Then select the I-shaped FRP profile 7 or the I-shaped FRP profile 8 with the inclined web, splicing the outer socket 10 of the profile with the outer tenon 9 of the fixed profile through the adhesive, and connect the flange on the other side of the profile with the box girder 1. The space is reinforced with expansion bolts 5. Repeat the above work, and finally select the C-shaped FRP profile with the outer socket 10 and the fixed profile to bond with the adhesive to form a closed continuous FRP hollow panel.

Considering that the bending moment of the concrete box girder bridge is larger at the mid-span position and the shear force is larger at the span edge position, the FRP profile 3 at the bottom of the concrete box girder is arranged at the mid-span position of the concrete box girder 1 when the bridge is reinforced, and the concrete The FRP profiles 4 on the side of the box girder are arranged at the cross-side position of the concrete box girder 1, and the specific arrangement length is calculated according to the actual reinforcement requirements.

Compared with the existing reinforcement structure, the reinforcement scheme of the concrete box girder bridge based on the FRP profile of the present invention makes full use of the advantages of the FRP material, such as light weight, high strength, corrosion resistance, and good designability. 5. Fixed on the bottom and side of the concrete box girder 1, effectively reinforcing the concrete box girder 1, and improving the overall stiffness and bearing capacity of the bridge without increasing the self-weight of the bridge.

Claims (2)

1. The utility model provides a concrete box girder bridge reinforcing scheme based on FRP section bar, includes concrete box girder (1), bridge deck pavement layer (2) are located concrete box girder (1) upper portion, its characterized in that: the box girder comprises a box girder body, and is characterized in that a box girder body bottom FRP section (3) is rigidly connected to the bottom of the box girder body (1), a box girder body side FRP section (4) is rigidly connected to the side of the box girder body (1), the box girder body bottom FRP section (3) comprises a C-shaped FRP section (6) and an I-shaped FRP section (7), and is spliced through an adhesive, and the box girder body side FRP section (4) comprises a C-shaped FRP section (6) and an I-shaped FRP section (8) with an inclined web, and is spliced through an adhesive.

2. The FRP profile-based concrete box girder bridge reinforcement scheme of claim 1, wherein: the FRP profiles (3) at the bottom of the concrete box girder are arranged in the region with larger bending moment in the span of the concrete box girder (1), and the FRP profiles (4) at the side of the concrete box girder are arranged in the region with larger shearing force at the span of the concrete box girder (1).

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